With the advancement of technologies and the improvement of people's living standard, electronic devices, such as smart phones and tablet computers, have become people's daily necessities. In the process of using an electronic device, the interaction between a user and the electronic device is usually performed through means such as a keyboard, a touch screen, a microphone and a camera built in or connected to the electronic device.
To be noted, the above introduction to the technical background is just made for the convenience of clearly and completely describing the technical solutions of the present disclosure, and to facilitate the understanding of a person skilled in the art. It shall not be deemed that the above technical solutions are known to a person skilled in the art just because they have been illustrated in the Background section of the present disclosure.